Method of casting annealing box covers



H. E. SHELDON METHOD OF CASTING ANNEALING BOX COVERS April 14, 1931..

4 Sheets-Sheet Filed March8. 1929 Q INVEPQIHISFIG 5. J 4 M 9mm April 14,1931.

H. E. SHELDON IIB'IHOD 0F CASTING ANNEALING BOX COVERS Filed March 8,1929 II III I// 4 Sheets-Sheet 2 p 14, 1931- H. E. SHELDON 1,800,848

METHOD OF CASTING ANNEALING BOX COVERS Filed March 8, 1929 4Sheets-Sheet s Patented Apr. 14, 1931 UNITED STATES HARRY SHELDON, FPITTSBURGH, PENNSYLVANIA METHOD OF CASTING ANNEALING BOX COVERSApplication filed March 8, 1929. Serial No. 345,417.

This invention relates to the casting in sand molds of annealing boxcovers or tops and more particularly to the casting of relatively largetops or covers such as used in box annealin sheets.

Annealing l iox covers or tops used in sheet annealing of course vary insize but a typical cover is one about 134" long, 52 wide by about 61high. It is essential that these cov- 11) ers be relatively thin and yetgas tight. Some tops or covers of about the above dimensions are ofsubstantially equal thickness throughout, with such thickness notmorethan 1".

This relatively thin section makes an extremely difficultcastingproposition as heretotore carried out for so far as I know thesehave always been cast with the top of the cover uppermost in the mold.The mold cavity has been vented at numerous places so and bottom pouringhas been resorted to.

This methochwhich so far as I know, has

been universal, has led to more or less spongy areas in the top of thecover especially if the section is thin.

An object of this invention is to provide an easy method of castingthin, relatively large, annealing box covers or tops; a method by meansof which thin walled gas tight covers can be cast with a minimum of lossso and from any ferrous alloy no matter hoW great is its linearcoefficient of expansion.

This, as well as other objects, which will readily appear to thoseskilled in this particular art, I attain by means of the methoddescribed in the specification and diagrammaticallyillustrated in thedrawings accompanying and forming part of this application.

The method broadly consists in forming 49 a mold cavity conforming,except for shrinkage. to the box cover or top to be cast; in sopositioning such cavity that the top of the cast cover will be in thebottom of the cavity and the sides and ends will extend to the top 5 ofthe cavity which is left open for venting. Bottompouring is resortedtoand the riser cavity connects with the mold cavity on oppo site sides ofone end thereof. The sand core is so supported that it may be collapsedas #10 soon as the cast metal has set, in order to remove the apossibility of those shrinkage strains which would be set up if the corewere not collapsed.

The inner portion of the sand mold core is hollow and is separately andcollapsibly supported at its sides and bottom. When the molten metal hasbeen poured intothe cavity of the; mold, which cavity is formed entirelyoi such material as sand, and after this metal has, at least, beenpartially solidified, the bottom support of the core is removed, andsubsequently, the side support is removed. Then, the top of the mold iscovered with metal sheeting and sand until the casting has com pletelycooled. In this manner, a very high grade type of metal casting isproduced.

As soon as the metal hasset, the core is col: lapsed and a removed, andthe flask is then covered with sheet metal and sand in order to causethe casting to cool slowly. VVhon the casting has cooled to the desiredpoint, it is removed from the flask, the riserand the arms connectingthe riser to the. casting are removed and the casting otherwise cleanedand made ready for use.

In order to enable others to understand this invention, I have includeddrawings in this application which illustrate one apparatus which may beused in carrying out my method.

In the drawings, Figure 1 is a top plan view of a mold cavity such asmay be utilized in carrying out my method. In order to illustrate themold cavity, I have shown in top plan, the flask, the mold formed withinthe flask, the core frame, with the sand core thereon, suspended inproper position within the mold whereby the mold cavity is formedbetween the mold and the core. I

Fig. 2 is a longitudinal sectional view of the elements shownin Fig. 1,but in this view it is assumed that the mold cavity is filled withmolten metal. It is assumed that the view is taken at the instant pouring is finished and before the core is collapsed.

Fig. 3 is a sectionalview in elevation taken on line 33 of Fig. 1 and italso assumes that the mold cavity is filled with molten metal.

Fig. 4 is a View in some respects similar to Fig. 3 since it is taken onthe same line but the mold, as well as the sand core is omitted and thecore supporting device is shown as itappears during the core collapsingoperation.

In carrying out my method, I form a mold cavity 5 in a sand mold 6 andbetween the mold and a collapsible core 7. In Fig. 1, I show the moldcavity before the metal is poured. I utilize bottom pouring and pourthrough an opening 8 having a single vertical channel 9 (Figs. 1 and 2)and branch channels 10 which connect with the'mold cavity at the bottomthereof, as shown in Fig. 2, and at opposite sides of one end thereof.

Since I cast the covers in inverted position, the pouring channelsconnect with the inold cover at a point which in the finished cover willbe adjacent one end thereof near its top to insure that the top of thecover is'cast from the hottest metal. This insures homogenco us gastight tops, for whatever impurities there are in the metal will rise inthe mold cavity to the top thereof and will appear in the covers at thebottom of the sides and ends. When the bottoms of thecovers are facedofl, these impurities, which could cause porous spots, are removed. V i

As soon as the pouring is finished and the casting sets the core 7 iscollapsed inorder to allow the metal to shrink without setting up suchstrains as would occur if-the core were not collapsed.

' In casting the cover of ferrous alloys-containingrelatively highpercentages of certain alloy elements such for example as chromium andnickel, this is most important, because of the relatively greatcoefficient of linear expansion of such alloys.

In the drawings, I have illustrated one method of collapsing the core.Obviously, other methods may be employed,jbut since it is important thatthe core be collapsed quickly and effectively, I prefer to use a coresupport such as shown in the drawings.

ing core.

like frame 15.

This core support consists of two side members, two end members and abottom member and means for holding said membersin core supportingposition and for moving the same to collapse the core. The outersurfaces of the side members 11, end members 12 and bottom member 13 areprovided with gaggers 14 forfacilitating adhesion between the outersurfaces of these members and the'sand form- Suspended in positionwithin the space defined by the side and end members is a box- 7 The topof this frame isopen and the bottom which is closed, forms the bottom ofthe core support, or rather the central sectionof the bottom of the coresupport, since the sides as well as. the ends extend inwardly at theirbottoms as shown at 16 and17. hen the frame is in supportingposition asshown in Figs. 2 and 3, its bottom lines 'nuts and at up with theinwardly extending bottom portions of the sides and ends.

Frame 15 is more or less rigidly secured to a support frame 18, which,prior to and during casting is supported on the top of the flask 19within which the mold is formed. The connection between supporting frame18 and frame 15 is made by means of four rods or bolts 20 which projectthrough the support frame at 21 and through cars 22 which projectinwardly from frame 15. Spacers 23, one for each pair ofrods or bolts20, are interposed between the top of frame 15 and the bottom ofsupportframe 18, so that, even though there is a considerable space between thebottom of support frame-18 and the top of frame 15 a more orless-rigidconnection between these frames is secured. In the castingoperation, the supporting frame or top 18 remainsin place during thepouring, and thence, the bottom core is lifted with the frame 18,permitting the hot gases to escape moment-arily'during the collapsing ofthe core. But, to pr'eventvaluable heat from escaping and to allow thecasting to cool slowly,'the top may be covered with suitable sheetingj 17 Secured to the sides-of frame 15 adjacent its opposite ends andbyfmeans ofscrews 24, are wedgeelike members'25. These members projectoutwardly from frame 15 and have a dovetailed connection 26 (Fig. 1)with reversely arranged wedge-like members 27 which are secured 'to andproject inwardly from the inner'sides of side members 11.

The ends of frame'15 adjacent their centers are also provided withoutwardlyextendingwedge-like members 28 Figs.'1 and 2, corresponding towedge-like members 25, and these'members 28 dovetail with reverselyarranged members '29 which are secured to and project inwardly fromend'members 12.

When the'v mold supportis in supporting condition,'it appears asillustrated in Figs. 2

and 3. The central member -15' is rigidly secured'to's'upport frame 18by means of rods 20 which carry at their lower threaded ends their upperthreaded" ends nuts31.

Hold-down screws ,32 threaded through support frame18 have their lowerends hollowed'out to receive' balls 33. The hollowed ends are peenedover so that the balls are retained in position, yet have thecapabilityof rotating. These balls bear on the top surface of side members 11 andhold these-members in core supporting position.' I

Screws 33 which are also threaded throug support frame 18. and which areidentical with screws 32, and are also provided with ball ends,- bear onthetop surface of end mem-' bers 12 when the core support is insupporting condition; 1 Y

Positioned at the center of each end memincomes her and hinged theretoas shown at 34, Fig. 1, is a supporting dog 34. This dog at its free endis provided with an opening 35 which extends therethrough from top tobottom, and, lying within this opening is a key holder 36. This keyholder is formed in the nature of a pin which is threaded into the topmember of wedge 28 and is enlarged at its upper end and provided with alaterally extending slot for the reception of a key 37.

When the core support is in supporting condition as in Figs. 2 and 3,keys 37 extend through slots in members 36 and thereby rigidly hold endmembers 12 in supporting position and prevent the same from moving downbelow supporting position.

Each of the side members 11 is provided with two inwardly extending ears38 and each of these ears supports a rod 39. The lower end of each rod39 is bifurcated and straddles its car 38 to which it is secured bymeans of a pin 10.

When the parts are assembled, these rods extend up through holes formedtherefor in support frame 18. Each rod immediately above spacer 23 isprovided with a laterally extending slot for the reception of a key 41,and, adjacent its top is provided with another laterally extending slot42.

\Vith the assembly in supporting condition, keys 41 are in the lowerslots as shown in Fig. 3, but when pouring is completed, keys 41 areremoved from their lower position and are inserted in slots 42, so thatwhen support frame 18 is moved to the position shown in Fig. l, keys 41will contact with the top surface of support frame 18, and lift sidemembers 11 with the center member 15.

At the same time, keys 41 are placed in the upper slots of rods 39, keys37 are removed from their slots. By removing keys 37 dogs 34 are allowedto swing upwardly about their pivot pins as the support frame 18 islifted, thus allowing end members 12 to move inwardly or downwardly withrelation to the upward moving center member 15. In other words, ascenter member 15 is raised, because of its attachment to support frame18 as said frame is raised, the end and side members move inwardly ortoward center member 15, thus collapsing the core support and the corecarried thereby.

The end and side members are so formed that when the assembly is insupporting condition, or position, a spaceis left at the mitre jointsbetween these. members and this space, which is shown by dotted lines at43 Fig. 1, is closed or covered by means of sheet metal strips 1 1.These strips are bent so as to close the corner openings and lap overthe sides and ends, and, are formed so as to extend underneath the coresupporting surfaces of the side and end members at the corners, as shownin Fig. 1 at 43. These are held in place by the sand forming the core,and, when the core is collapsed, they place. l lin preparing for a castthe" mold 6 is formed within the flask in the manner in which dry sandmolds are ustially-formed. The mold surfaces are swept aard the moldbaked.

The mold support suspended from support fra 1ne18is covered with sand '1and brought to the proper contour in the usual manner as by sweeping andis then baked. i

I laving thus described my invention, what I claim as new and desire tosecure by Letters Patentis:- i

1. The method of casting an annealing bot;

cover which consists in preparing a sand mold, in separately supportingthe sides and bottom of the core of the mold, in bottom pouring moltenmetal into the mold, and when the metal beginsto solidify, in removingthe support of the bottom of the core of the mold, and subsequently,- inremoving the support of the sides, of the core of the mold.

2. The method of casting annealing box cover which consists in preparinga sand mold, in separately supporting the sides and bottom of the coreof the mold, in pouring molten metal into the cavity of the mold, incollapsing the bottom support of the core of the mold, and'subsequently,in coll'apsingthe side support of the core of the mold, and in coveringthe top of the mold until the metal is completely cooled. r

3. The method of casting an annealing box cover which consists inpreparing a sand mold, in separately supporting the sides and bottom ofthe core of the mold, in bottom pouring molten metal into the mold, andwhen the metal begins to solidify, in removing the support of the bottomof the core of the mold, and subsequently, in removing the support ofthe sides of the core of the mold, and in covering the top of the moldduring the coolingof the metal.

4. The method of casting an annealing box cover which includes preparinga sand mold, supporting the sides and bottom of the core of the mold,pouring molten metal into the mold, and when the metal begins tosolidify, in separately removing the support of the bottom of the coreof the mold and the sup port of the sides of the core of the mold.

5. The method of casting an annealing box cover which includes preparinga sand mold,

supporting the sides and bottom of the core of the mold, pouring moltenmetal into the mold, and when the metal begins to solidify, separatelyremoving the support of the bot tom of the core of the mold and thesupport of the sides of the core of the mold,'and covering the top ofthe mold during the cooling of the metal.

6. The method of casting an annealing box cover which includes preparinga sand mold,

easily forced outseparately supporting the sides and bottom of the coreof the mold, bottom pouring molten metal into the mold, and when themetal begins to solidify, separately removing the support at the bottomof the core of the mold and the supportof thesides of the core of themold.

,7. The method of casting an annealing box cover which includespreparing a sand mold, separately supporting the sides and bottom of thecore of the mold, pouring molten metal into the mold, and when the metalbegins to solidify,.removing the sup port of the bottom of the core ofthe mold, and subsequently, removing the: support of the sides of thecore of the mold; 7

8. The method of casting an-annealing box cover which includes preparinga sand mold, separately supporting the sides and bottom of the. core ofthe mold, pouring molten metal into the cavity of the mold, collapsingthe bottom support of the core of the mold, and subsequently, collapsingthe: side support of the core of the mold.

9. The method of casting an annealing box cover which includes preparinga sand mold, separately supporting the sides and bottom of the coremold, pouring metal into the mold, and when the metal begins tosolidify, separately collapsing the support of the bottom of the core ofthe mold andthe support of the sides of the core of the mold. V

In testimony whereof, I have hereunto subscribed my name this 5th day ofMarch,

- HARRY E. SHELDON.

